1.1. Sebaceous cyst
Sebaceous cysts are common, noncancerous cysts of the skin. Cysts are atypical growths in your body that may contain liquid or semiliquid material. Sebaceous cysts are mostly found on your face, neck, or torso. They grow slowly and aren’t life threatening, but they may become uncomfortable if they go unchecked. Doctors usually diagnose a cyst with only a physical examination and your medical history. In some cases, a cyst will be examined more thoroughly for signs of cancer. Sebaceous cysts form out of your sebaceous gland. The sebaceous gland produces the oil (called sebum) that coats your hair and skin. Cysts can develop if the gland or its duct (the passage from which the oil is able to leave) becomes damaged or blocked. This usually occurs due to trauma to the area. The trauma may be a scratch, a surgical wound, or a skin condition, such as acne. Sebaceous cysts grow slowly, so the trauma may have occurred weeks or months before you notice the cyst. Your doctor can treat a cyst by draining it or by surgically removing it. Usually, cysts are removed. This doesn’t mean they’re dangerous — it may be for cosmetic reasons.